The invention relates to a television signal decoder for separating a chrominance signal and its corresponding luminance signal from a time division multiplexed component television signal such as standard Multiplexed Analog Component (MAC) signal.
The invention also relates to a decoder capable of extracting an equal or smaller aspect ratio picture information from a high definition television signal that provides extended aspect ratio picture information, such as a high definition MAC signal or a high definition frequency multiplexed component signal such as a high definition NTSC signal.
In an NTSC television system, for example, the ratio of the picture width to its height at the display device is 4:3. This ratio is called the aspect ratio. Recently, there has been an interest in using wider aspect ratios for television systems such as 2:1 or 5:3 ratios, which more nearly equal the ratio of width to height that is viewed by the human eye. The 5:3 aspect ratio has received particular attention since release prints for motion pictures film in the United States employ this ratio and thus the pictures of such prints may be transmitted and received without cropping.
It may be desirable to provide video information of a picture having extended aspect ratio in a MAC signal format, for example. In such a case, the MAC signal is called a high definition MAC signal.
It may be also desirable to display a high definition MAC signal in a receiver having a smaller aspect ratio display, by displaying only that portion of the picture which fits the display.
One feature of the invention is a decoder for receiving a high definition television signal such as high definition MAC signal, and for selectively providing video signals compatible with the aspect ratio of the television receiver such that the corresponding picture is displayed in such receiver without suffering dimensional distortions. This flexibility in selectively cropping out a portion of the transmitted picture to fit the television receiver may be achieved by the decoder of the invention without unduly complicating its circuits.